baskduf/FableCodex

What is FableCodex?

FableCodex is a Codex plugin that adds a disciplined, evidence‑based workflow to any task you ask Codex (the code‑generation model) to perform. Instead of letting the model edit files unchecked, the plugin makes Codex:

Classify the request before acting.
Inspect the current workspace and any referenced sources.
Use the appropriate Codex‑native tools (e.g., file‑edit, test runner) rather than relying on memory.
Track a multi‑step goal ledger, recording evidence at each checkpoint.
Collect review findings and keep them open until they are explicitly resolved.
Verify the result with tests, linters, type‑checks, screenshots, command output, etc.
Report what changed, what was verified, and what risk remains.

The plugin does not modify the underlying model, its weights, or its safety systems – it only adds procedural guidance and local bookkeeping.

Who might want to use it?

Good fit	Not a good fit
Multi‑step implementations, refactorings, or migrations	One‑line fixes or tiny edits
Debugging hard‑to‑reproduce failures	Simple brainstorming or idea generation
CI failures, release work, security‑sensitive changes	Tasks where the extra overhead outweighs the benefit
Reviews where findings must block completion	Quick “look‑and‑say‑done” answers
Teams that already have access to a Codex model and want stricter process	Users without a Codex integration

How does a user control the workflow?

Control is done entirely through the prompt you send to Codex, using the @codex-fable5 tag. Examples:

Strict mode – full ledger, findings gate, and verification before finishing:

@codex-fable5 Run this strictly.
Use a goal ledger, record any review findings, and do not finish until tests and findings gate pass.

Analysis only – no file edits, just a report of findings:

@codex-fable5 Analyze only.
Do not edit files. Give findings with file and line references.

Implementation with limits – edit but don’t push or delete branches:

@codex-fable5 Implement the fix.
Do not commit, push, or delete branches.
Run unit tests and report any residual risk.

Debugging – reproduce, hypothesise, gather disconfirming evidence, then fix:

@codex-fable5 Debug this failure.
Reproduce it first, keep multiple hypotheses, gather disconfirming evidence, then fix and verify.

Core concepts

Goal Ledger

Stored locally in .codex-fable5/goals.json.
Created with codex-fable5 goals create … specifying a brief description and a list of sub‑goals.
Each sub‑goal is marked complete with codex-fable5 goals checkpoint …, supplying evidence (e.g., “read file X, updated tests”) and optionally a verification command and its output.

Findings Gate

Review issues are recorded in .codex-fable5/findings.json via codex-fable5 findings add ….
A finding stays open until it is resolved with codex-fable5 findings resolve …, which also requires verification evidence.
codex-fable5 findings gate aborts final completion if any high‑severity or blocked findings remain.

Quick start (from the README)

# Install the latest stable release
codex plugin marketplace add baskduf/FableCodex --ref v0.5.1
codex plugin add codex-fable5@fablecodex

# Restart Codex, then invoke the skill in your prompt
@codex-fable5 Use this skill to implement the change.
Create a goal ledger if the work has multiple steps.
Track findings before final completion.
Run the project tests before saying it is done.

A lighter version skips the ledger:

@codex-fable5 Review this quickly.
Do not create a goal ledger. Check the key evidence and report only actionable findings.

Command reference (summary)

Command	What it does
`codex-fable5 status`	Shows current goals and findings
`codex-fable5 goals create …`	Starts a new multi‑step ledger
`codex-fable5 goals next`	Shows the next pending goal
`codex-fable5 goals checkpoint …`	Marks a goal as complete/failed with evidence
`codex-fable5 findings add …`	Records a review finding
`codex-fable5 findings resolve …`	Closes a finding with verification evidence
`codex-fable5 findings gate`	Fails if any open/blocked findings remain
`codex-fable5 update`	Pulls the latest stable tag of the plugin

Additional features

Coverage accounting – if you have the original CLAUDE‑FABLE‑5.md source, a helper script can verify that every source heading has a corresponding decision (implemented, adapted, unsupported, or N/A).
Optional provider bridge – documentation is provided for routing requests through Anthropic or an OpenAI‑compatible gateway (e.g., LiteLLM). The plugin itself does not ship any model credentials.
Local state – all ledgers and event logs live under .codex-fable5/ and are meant to be transient; commit only if you deliberately want a permanent transcript.

License & community

Licensed under AGPL‑3.0‑or‑later.
Recognised in community skill lists such as antigravity-awesome-skills and awesome-agent-skills.
Contributions are welcomed; a contributors badge is displayed in the README.

TL;DR

FableCodex is a process‑oriented wrapper for the Codex code‑generation model. By making the model follow a checklist‑style workflow—goal ledgers, evidence checkpoints, findings gates, and automated verification—it helps teams avoid missed steps in larger, safety‑critical code changes while staying completely within the Codex ecosystem.